Nav: Added NavMoveResultParentId internal info to record when the parent/context of a given NavId. Useful for various algorithms (currently looking at range selection stuff) (#787)

imgui.cpp

@@ -2220,6 +2220,7 @@ bool ImGui::ItemAdd(const ImRect& bb, const ImGuiID* id, const ImRect* nav_bb_ar
                 if (new_best)
                 {
                     g.NavMoveResultId = *id;
+                    g.NavMoveResultParentId = window->IDStack.back();
                     g.NavMoveResultRectRel = nav_bb_rel;
                 }
 
@@ -2856,6 +2857,7 @@ static void NavUpdate()
 
     // Reset search 
     g.NavMoveResultId = 0;
+    g.NavMoveResultParentId = 0;
     g.NavMoveResultDistAxial = g.NavMoveResultDistBox = g.NavMoveResultDistCenter = FLT_MAX;
 
     // When we have manually scrolled (without using navigation) and NavId becomes out of bounds, we clamp its bounding box (used for search) to the visible area to restart navigation within visible items

imgui_internal.h

@@ -480,6 +480,7 @@ struct ImGuiContext
     ImGuiDir                NavMoveDir;                         // West/East/North/South
     ImGuiDir                NavMoveDirLast;                     //
     ImGuiID                 NavMoveResultId;                    // Best move request candidate
+    ImGuiID                 NavMoveResultParentId;              //
     float                   NavMoveResultDistBox;               // Best move request candidate box distance to current NavId
     float                   NavMoveResultDistCenter;            // Best move request candidate center distance to current NavId
     float                   NavMoveResultDistAxial;
@@ -590,6 +591,7 @@ struct ImGuiContext
         NavMoveRequestForwardStep = 0;
         NavMoveDir = NavMoveDirLast = ImGuiDir_None;
         NavMoveResultId = 0;
+        NavMoveResultParentId = 0;
         NavMoveResultDistBox = NavMoveResultDistCenter = NavMoveResultDistAxial = 0.0f;
 
         SetNextWindowPosVal = ImVec2(0.0f, 0.0f);